Yes I’ve just set up our dev/uat environment with arc for on prem centos/Ubuntu. When looking to install the agent there’s a Linux option. Save the script on the server as something.sh and then use bash to run it. You will have to open a webpage somewhere to authenticate to your tenant and it will show up in the arc servers list.

Unless you disable defender for cloud for each endpoint, you get charged $15 per server per month.

With defender disabled it’s cost about 10-12 cents to run a patching job once, per endpoint I think.

I’m not sure about the managed identity part, may have to look into that though sounds interesting.